"""Bounded post-exhaustion auto-recovery ladder for a pre-delivery turn (#85426, #107307).

Runs from ``settle_unrecovered_error`` once ``max_retries`` is spent AND the fallback chain has
nothing left to move to (fallback stays first). While the provider is only *temporarily* away
(5xx, overloaded/529, connect/read timeouts) and no answer text has reached the user yet, the
turn parks with a visible countdown instead of ending in "API failed after N retries", then
re-enters the ordinary retry loop. Cycles: ``agent.auto_recovery_cycles`` (default 5) with a
jittered 15/30/60/60/60 s schedule; a provider ``Retry-After`` wins up to 120 s. Non-retryable
classes (auth, format, content policy, billing, entitlement) never enter, and an interrupt
cancels the wait cleanly. Overload-class errors use this same schedule — there is no separate
overload backoff path.
"""

from __future__ import annotations

import logging
from typing import Any, Dict, Optional

from agent.error_classifier import FailoverReason

logger = logging.getLogger("agent.conversation_loop")

# Transient transport verdicts: the provider is expected back. Everything else (auth, format,
# content policy, billing, entitlement, overflow, model-not-found ...) is deterministic for this
# request and stays out.
_LADDER_REASONS = frozenset({FailoverReason.overloaded, FailoverReason.server_error, FailoverReason.timeout})

_LADDER_BASE_DELAY_S = 15.0
_LADDER_CAP_S = 60.0
# A provider that names its own cooldown knows better than the schedule, within reason.
_RETRY_AFTER_CAP_S = 120.0

# How the user stops the wait on this surface; the ladder text must say so plainly.
_STOP_HINTS = {
    "cli": "press Esc to stop",
    "tui": "press Esc to stop",
    "desktop": "press Esc to stop",
    "api_server": "cancel the request to stop",
    "cron": "",
}
_DEFAULT_STOP_HINT = "send /stop to cancel"


def auto_recovery_cycles(agent: Any) -> int:
    """Configured ``agent.auto_recovery_cycles`` (0 disables the ladder)."""
    return max(int(getattr(agent, "_auto_recovery_cycles", 0) or 0), 0)


def _retry_after_seconds(api_error: Any) -> Optional[float]:
    """Provider-declared cooldown from the ``Retry-After`` header or a ``retry_after`` body field."""
    from agent.retry_utils import parse_retry_after_seconds
    value = parse_retry_after_seconds(getattr(getattr(api_error, "response", None), "headers", None))
    if value is None:
        body = getattr(api_error, "body", None)
        if isinstance(body, dict):
            nested = body.get("error")
            value = parse_retry_after_seconds((nested if isinstance(nested, dict) else body).get("retry_after"))
    return value if value is not None and value > 0 else None


def ladder_wait_seconds(cycle: int, api_error: Any) -> float:
    """Wait before recovery ``cycle`` (1-based): jittered 15/30/60/60/60 s, or the provider's
    ``Retry-After`` when present (honoured past the 60 s cap, up to 120 s)."""
    from agent.retry_utils import jittered_backoff
    retry_after = _retry_after_seconds(api_error)
    if retry_after is not None:
        return min(retry_after, _RETRY_AFTER_CAP_S)
    return jittered_backoff(cycle, base_delay=_LADDER_BASE_DELAY_S, max_delay=_LADDER_CAP_S, jitter_ratio=0.2)


def ladder_eligible(agent: Any, classified: Any) -> bool:
    """True when the ladder may engage: cycles configured, a transient transport verdict, and no
    answer text streamed to the user yet (delivered text is never replayed by this path)."""
    if auto_recovery_cycles(agent) <= 0 or classified.reason not in _LADDER_REASONS:
        return False
    streamed = getattr(agent, "_current_streamed_assistant_text", "") or ""
    return not agent._has_content_after_think_block(streamed)


def ladder_notice(agent: Any, *, wait_s: float, cycle: int, total: int) -> str:
    hint = _STOP_HINTS.get(str(getattr(agent, "platform", "") or "").lower(), _DEFAULT_STOP_HINT)
    text = f"⏳ Provider temporarily unavailable — retrying automatically in {wait_s:.0f}s (cycle {cycle}/{total})"
    return f"{text}; {hint}" if hint else text


def auto_recover_after_exhaustion(
    agent: Any, api_error: Any, classified: Any, _retry: Any, *, messages: Any,
    conversation_history: Any, api_call_count: int,
) -> Optional[Dict[str, Any]]:
    """Run one recovery cycle after retries + fallback exhausted. Returns ``{"action": "continue"}``
    when the wait completed (caller zeroes ``retry_count`` and re-enters the retry loop),
    ``{"action": "break"}`` when a steering correction arrived mid-wait, ``{"action": "return",
    "result": …}`` when the user interrupted, and ``None`` when the ladder does not apply or is spent."""
    from agent.turn_recovery import interruptible_backoff_sleep

    if not ladder_eligible(agent, classified):
        return None
    total = auto_recovery_cycles(agent)
    used = int(getattr(_retry, "auto_recovery_cycles_used", 0) or 0)
    if used >= total:
        agent._emit_diagnostic_status(
            f"⏳ Automatic recovery gave up after {total} cycles — the provider is still unavailable."
        )
        return None
    cycle = used + 1
    _retry.auto_recovery_cycles_used = cycle
    wait_s = ladder_wait_seconds(cycle, api_error)
    notice = ladder_notice(agent, wait_s=wait_s, cycle=cycle, total=total)
    # Durable line on every surface (CLI print, TUI status.update, gateway bubble, api_server SSE)
    # plus the live wait line (spinner / thinking.delta / activity heartbeat).
    agent._emit_diagnostic_status(notice)
    agent._emit_diagnostic_wait(notice)
    logger.warning(
        "%sProvider unavailable (%s) — auto-recovery cycle %d/%d, retrying in %.0fs %s",
        agent.log_prefix, classified.reason.value, cycle, total, wait_s, agent._client_log_context(),
    )
    interrupted = interruptible_backoff_sleep(
        agent, wait_s, _retry, messages=messages, conversation_history=conversation_history,
        api_call_count=api_call_count,
        abort_message="Interrupt detected during automatic recovery wait, aborting.",
        interrupt_text=f"Operation interrupted: waiting for the provider to recover (cycle {cycle}/{total}).",
        activity_label=f"auto-recovery wait ({cycle}/{total})",
    )
    if interrupted is not None:
        return {"action": "return", "result": interrupted}
    if _retry.restart_with_redirected_messages:
        return {"action": "break"}
    return {"action": "continue"}